Liquid drop microreactor

Abstract

The invention discloses a droplet microreactor, and belongs to the technical field of microfluidics. The liquid drop generator is integrated by multiple layers of liquid drop generators, a fluid distribution channel is etched on each layer of liquid drop generator, a first inlet of each layer of first channel unit is connected with at least two second distribution channels through a first distribution channel, and a plurality of third distribution channels are evenly distributed on each second distribution channel in the flowing direction. The total path of the first fluid flowing from the first inlet to the outlet end of each third distribution channel is equal; the design of the second channel unit is consistent with that of the first channel unit; the outlet ends of the third distribution channels are connected with the outlet ends of the third distribution runners of the second channel unit in a one-to-one correspondence manner, so that the first fluid and the second fluid collide and shear to form liquid drops; according to the invention, the flux can be improved, the fluid distribution is uniform, and the conversion from laboratory achievements to business and industry can be promoted.

Description

Technical Field

[0001] The present invention relates to the field of microfluidic technology, and particularly to a droplet microreactor. Background Art

[0002] Due to its advantages of efficient heat and mass transfer, rapid and controllable reaction, low cost and easy large-scale production, droplet microfluidic technology has been widely used in fields such as emulsion preparation, chemical reaction, drug delivery and functional material preparation in recent years. Compared with traditional preparation methods such as mechanical stirring, droplet extrusion and emulsification, microfluidic technology can provide a new way for preparing highly monodisperse droplets by precisely controlling the fluid flow of two phases. The highly monodisperse droplets generated in micro-devices have now been widely used as templates for the controllable preparation of functional microspheres. However, existing microfluidic devices (such as T-shaped, flow-focusing and coaxial annular microchannels) are mostly single-channel designs, with limited droplet generation flux and difficult to meet the requirements of industrial production. The low productivity largely restricts the transformation of droplet microfluidic technology from laboratory to commercial / industrial. If, in order to pursue high throughput, the single-channel design is simply adjusted to a multi-channel design, uneven fluid distribution is likely to occur during multi-channel integration, resulting in a widened droplet size distribution and affecting product consistency, further restricting the industrial transformation of the technology. Summary of the Invention

[0003] The object of the present invention is to overcome the problems in the prior art and provide a droplet microreactor that can improve the flux and has uniform fluid distribution, which helps to promote the transformation of laboratory results to commercial and industrial applications.

[0004] A droplet microreactor of the present invention is integrated by multiple layers of droplet generators. Each layer of droplet generator includes a substrate and a fluid distribution channel etched on the substrate. The fluid distribution channels of each layer include a first channel unit for the first fluid distribution and a second channel unit for the second fluid distribution; The first channel unit includes a first inlet, and the first inlet is respectively communicated with at least two second distribution channels through a first distribution channel. A plurality of third distribution channels are evenly distributed along the flow direction on each of the second distribution channels. The first fluid entering through the first inlet enters each of the third distribution channels along the first distribution channel and each second distribution channel; and the total distances that the first fluid flows through from the first inlet to the outlet ends of each of the third distribution channels are equal. The second channel unit includes a second inlet, and the second inlet is respectively communicated with at least two second distribution channels through a first distribution flow channel. The second distribution channels and the second distribution channels correspond to each other one by one; a plurality of third distribution channels are evenly distributed along the flow direction on each of the second distribution channels, and the third distribution channels and the third distribution channels correspond to each other one by one; the second fluid entering through the second inlet enters each of the third distribution channels along the first distribution flow channel and each second distribution channel; and the total distances that the second fluid flows through from the second inlet to the outlet ends of each of the third distribution channels are equal. The outlet ends of each of the third distribution channels and the outlet ends of each of the third distribution channels are connected to each other one by one, so that the first fluid and the second fluid collide and shear at the connection to form droplets; the droplets are respectively connected to each droplet outlet through each dispersion channel arranged in one-to-one correspondence; the first inlets, the second inlets and each droplet outlet on each layer of droplet generator are communicated up and down.

[0005] Preferably, each of the third distribution channels, each of the third distribution channels and each of the dispersion channels are combined into multiple groups. Each group includes a third distribution channel, a third distribution channel and a dispersion channel. The third distribution channel and the third distribution channel of each group are respectively vertically arranged on both sides of the dispersion channel. The outlet ends of the third distribution channel and the outlet ends of the third distribution channel are both connected to the dispersion channel, and the outlet ends of the third distribution channel and the outlet ends of the third distribution channel are arranged in a staggered manner along the flow direction of the fluid, so that the outlet ends of the third distribution channel and the outlet ends of the third distribution channel are partially opposite to each other.

[0006] Preferably, the channels of each of the third distribution channels near the outlet ends are arc-shaped bends, so that the first fluid entering through the third distribution channel and the second fluid entering through the third distribution channel are dispersed under the action of an asymmetric shear force.

[0007] Preferably, each of the second distribution channels and each of the second distribution channels are both meandering structures, and the bends of the meandering structures are all rounded corners.

[0008] Preferably, the meandering structures of each of the third distribution channels have the same number of turns; and / or the meandering structures of each of the third distribution channels have the same number of turns.

[0009] Preferably, the meandering structures of the third distribution channel and the third distribution channel communicated with the same dispersion channel are the same.

[0010] Preferably, the inner wall of the fluid distribution channel has a hydrophilic coating or a hydrophobic coating.

[0011] Preferably, each dispersion channel includes a first section and a second section that communicate with each other. The inner diameter of the second section is greater than that of the first section, and the other end of the first section is connected to the connection between the third distribution channel and the third distribution flow path, and the other end of the second section is connected to the droplet outlet.

[0012] Preferably, each dispersion channel has the same meandering structure.

[0013] Preferably, the first inlet, the second inlet, and each droplet outlet have a circular cross-section, and the first inlet and the second inlet are both located at the midpoint positions of the first distribution channel and the first distribution flow path.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention designs a multi-layer droplet generator and integrates the multi-layer droplet generator into one; in each layer of the droplet generator, the first fluid entering from the first inlet is distributed into multiple groups through a plurality of second distribution channels; and then the fluid in each second distribution channel is redistributed into multiple groups through a plurality of third distribution channels. Similarly, the second fluid entering from the second inlet is distributed into multiple groups through a plurality of second distribution flow paths; and then the fluid in each second distribution flow path is redistributed into multiple groups through a plurality of third distribution flow paths; realizing the parallel preparation of droplets, significantly improving the throughput, and providing a feasible path for the transformation of laboratory results into industrial production.

[0015] In order to make the liquid distribution in each channel or flow path uniform, the present invention uses high-precision lithography technology to process and etch the fluid distribution channel; at the same time, through the way of path compensation, it ensures that the flow paths in each channel and each flow path are the same; at the same time, through the design of rounded corners, the pressure drop is reduced, avoiding the problem of uneven fluid distribution. At the same time, the fluid distribution channel etched by the present invention reduces the processing difficulty through an integrated design and improves the bonding success rate.

[0016] The present invention successfully prepares various functional microspheres such as chitosan, silica, polystyrene, and poly(silsesquioxane) by regulating the components such as monomers and cross-linking agents in the two-phase fluid. The integrated droplet microreactor of the present invention can also be adapted to various reaction types such as ultraviolet light curing and chemical cross-linking to meet the preparation requirements of different functional microspheres. Description of the Drawings

[0017] Figure 1 It is a plan view of the integrated and enlarged droplet microreactor according to the embodiment of the present invention.

[0018] Figure 2 It is a three-dimensional stereogram of the single-layer droplet microreactor according to the embodiment of the present invention.

[0019] Figure 3 This is a physical diagram of the single-layer droplet microreactor according to the embodiment of the present invention.

[0020] Figure 4 This is a device diagram for preparing water-in-oil emulsion, chitosan microspheres, and silica microspheres according to the embodiment of the present invention.

[0021] Figure 5 This is a diagram of droplet generation in channels 1 to 8 of the dispersion channel 6 in Example 1 of the present invention (operating flow rate: Q c = 10 μL·min -1 , Q d = 10 μL·min -1 ).

[0022] Figure 6 This is a diagram of droplet generation in the enlarged collection section of channels 1 to 8 of the dispersion channel 6 in Example 1 of the present invention (operating flow rate: Q c = 10 μL·min -1 , Q d = 10 μL·min -1 ).

[0023] Figure 7 This is a diagram of droplet generation in the enlarged collection section of channels 1 to 8 of the dispersion channel 6 according to the embodiment of the present invention (operating flow rate: Q c = 20 μL·min -1 , Q d = 10 μL·min -1 ).

[0024] Figure 8 This is a diagram of droplet generation in the enlarged collection section of channels 1 to 8 of the dispersion channel 6 according to the embodiment of the present invention (operating flow rate: Q c = 100 μL·min -1 , Q d = 100 μL·min -1 ).

[0025] Figure 9 This is a scanning electron microscope image of silica microspheres at different magnifications prepared in Example 4 of the present invention.

[0026] Figure 10 This is a scanning electron microscope image of silica microspheres at different magnifications prepared in Example 5 of the present invention.

[0027] Explanation of reference numerals: 1. First inlet; 2. Second inlet; 3. Droplet outlet; 4. First distribution channel; 5. Second distribution channel; 6. Third distribution channel; 7. First distribution flow path; 8. Second distribution flow path; 9. Third distribution flow path; 10. Dispersion channel, 101. First section; 102. Second section. Detailed implementation manners

[0028] To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Apparently, the described embodiments are some but not all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0029] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second" and similar terms used in the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" are intended to indicate that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, without excluding other elements or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to indicate relative positional relationships, and when the absolute positions of the objects being described change, the relative positional relationships may also change accordingly.

[0030] Based on the fact that the flux of droplets in a single channel in the prior art still cannot meet many downstream applications, which restricts the transformation of droplet microfluidics technology from the laboratory to commercial / industrial applications. Therefore, we designed an integrated and amplified droplet microreactor, and processed the fluid distribution channels of the droplet microreactor by lithography technology for high-throughput preparation of droplets. Using droplets as templates, chitosan, silica and poly(silsesquioxane) microspheres with uniform and controllable sizes and good monodispersity were respectively prepared by combining chemical cross-linking reactions and hydrolysis condensation reactions.

[0031] A droplet microreactor provided in this embodiment is integrated by multiple layers of droplet generators. Each layer of droplet generator includes a substrate and a fluid distribution channel etched on the substrate. The material of the substrate in this embodiment is PDMS, and the purpose of being transparent is to achieve better visualization effect. Of course, the substrate can also be made of materials such as silicon carbide and polytetrafluoroethylene. It should be noted that the lower surface of the upper substrate is the covering surface of the lower substrate. Therefore, as a more preferred embodiment, the lower surface of the upper substrate can seal the fluid distribution channel etched on the lower substrate. In this embodiment, the fluid distribution channels of each layer include a first channel unit for the first fluid distribution and a second channel unit for the second fluid distribution; as an example, in this embodiment, the first fluid is the continuous phase and the second fluid is the dispersed phase.

[0032] The first channel unit includes a first inlet 1. The first inlet 1 is respectively connected to at least two second distribution channels 5 through a first distribution channel 4. A plurality of third distribution channels 6 are evenly distributed along the flow direction on each of the second distribution channels 5. The first fluid entering through the first inlet 1 enters each of the third distribution channels 6 along the first distribution channel 4 and each second distribution channel 5; and the total distance that the first fluid flows from the first inlet 1 to the outlet end of each third distribution channel 6 is equal; the second channel unit includes a second inlet 2. The second inlet 2 is respectively connected to at least two second distribution channels 8 through a first distribution channel 7. The second distribution channels 8 correspond to the second distribution channels 5 one by one; a plurality of third distribution channels 9 are evenly distributed along the flow direction on each of the second distribution channels 8, and the third distribution channels 9 correspond to the third distribution channels 6 one by one; the second fluid entering through the second inlet 2 enters each of the third distribution channels 9 along the first distribution channel 7 and each second distribution channel 8; and the total distance that the second fluid flows from the second inlet 2 to the outlet end of each third distribution channel 9 is equal; The outlet ends of each of the third distribution channels 6 and the outlet ends of each of the third distribution channels 9 are connected in one-to-one correspondence, so that the first fluid and the second fluid collide and shear at the connection to form droplets; the droplets are respectively connected to each droplet outlet 3 through the correspondingly provided dispersion channels 10; the first inlets 1, the second inlets 2 and each droplet outlet 3 on each layer of droplet generator are connected up and down.

[0033] In each layer of droplet generator in this embodiment, the first fluid entering from the first inlet 1 is distributed into multiple groups through multiple second distribution channels 5; and then the fluid in each second distribution channel 5 is redistributed into multiple groups through multiple third distribution channels 6; realizing the parallel preparation of droplets, significantly improving the throughput, and providing a feasible path for the transformation of laboratory results to industrial production. In order to make the liquid distribution in each channel or flow channel uniform, this embodiment uses high-precision lithography technology to process and etch the fluid distribution channels; at the same time, through the way of path compensation, it is ensured that the flow paths in each channel and each flow channel are the same.

[0034] As a preferred embodiment, each of the third distribution channels 6, each of the third distribution flow channels 9, and each of the dispersion channels 10 are combined into multiple groups. Each group includes a third distribution channel 6, a third distribution flow channel 9, and a dispersion channel 10. The third distribution channel 6 and the third distribution flow channel 9 of each group are respectively disposed vertically on both sides of the dispersion channel 10. The outlet ends of the third distribution channel 6 and the third distribution flow channel 9 are both connected to the dispersion channel 10, and the outlet ends of the third distribution channel 6 and the third distribution flow channel 9 are arranged in a staggered manner along the flow direction of the fluid, so that the outlet ends of the third distribution channel 6 and the third distribution flow channel 9 are partially opposite to each other. The connection between the outlet end of the third distribution channel and the outlet end of the third distribution flow channel forms a dispersion structure. Therefore, the two outlet ends arranged in a staggered manner in this embodiment enable an asymmetric flow field to be generated at the dispersion structure. The asymmetric flow field structure can, on the one hand, strengthen the shear force during the droplet generation process. This shear force can stretch and break the dispersed-phase fluid into smaller droplets or bubbles, achieving a more uniform droplet or bubble size distribution and improving the quality and consistency of the dispersion effect. On the other hand, it can strengthen the mixing and mass transfer after the two-phase fluids meet, greatly increasing the droplet generation frequency and strengthening the chemical reaction between the two-phase fluids.

[0035] As a preferred embodiment, the channel of each third distribution channel 6 near the outlet end is an arc bend, so that the first fluid entering through the third distribution flow channel 9 and the second fluid entering through the third distribution channel 6 are dispersed under the action of an asymmetric shear force.

[0036] As a preferred embodiment, each of the second distribution channels 5 and each of the second distribution flow channels 8 are both serpentine structures, and the bends of the serpentine structures are all rounded corners. In this embodiment, the design of the rounded corners at the bends of the serpentine structure can significantly reduce the pressure drop, reduce the flow resistance, and avoid the occurrence of flow dead zones, making the fluid distribution more uniform. As a more preferred method, the number of bends of the serpentine structure is controlled within 4 times or less to avoid obvious flow resistance under a relatively large operating flow rate. It has been experimentally verified that when the number of bends of the serpentine structure is controlled within 4 times or less, the flow resistance is not obvious and the fluid distribution uniformity is good.

[0037] As a preferred embodiment, the serpentine structures of each of the third distribution channels 6 have the same number of turns; and / or the serpentine structures of each of the third distribution flow channels 9 have the same number of turns. This can make the fluid distributed into each of the third distribution channels 6 uniform; similarly, the same number of turns of each of the third distribution flow channels 9 can also make the fluid distributed into each of the third distribution flow channels 9 uniform.

[0038] As a preferred embodiment, the winding structures of the third distribution channel 6 and the third distribution flow channel 9 communicating with the same dispersion channel 10 are the same. When the distribution channels of the continuous phase and the dispersed phase have the same winding structure and the same number of bends, the flow path lengths and velocity distributions of the two fluids in the channels will be more consistent. Therefore, before entering the dispersion channel 10, the velocity and pressure distributions of the two fluids are more uniform, thereby reducing the instability and non-uniformity caused by the fluid velocity difference. At the same time, the same winding structure can ensure that the pressure fluctuations of the two fluids are consistent when entering the dispersion channel 10. This design can reduce the non-uniformity of the droplet or bubble sizes caused by the pressure difference, thereby improving the stability of the system.

[0039] As a preferred embodiment, the inner wall of the fluid distribution channel has a hydrophilic coating or a hydrophobic coating.

[0040] As a preferred embodiment, each dispersion channel 10 includes a first section 101 and a second section that communicate with each other. The inner diameter of the second section is larger than that of the first section 101, and one end of the first section 101 is connected to the connection between the third distribution channel 6 and the third distribution flow channel 9, and the other end of the second section is connected to the droplet outlet 3. The small inner diameter of the first section 101 can ensure that the dispersed-phase fluid has sufficient velocity and shear force when entering the dispersion area, which helps the formation and dispersion of droplets or bubbles. The larger inner diameter of the second section can increase the distance between droplets and reduce the collision and coalescence between droplets. In a larger channel, the movement paths of the droplets are more dispersed, reducing the interaction between droplets and facilitating the collection of droplets.

[0041] As a preferred embodiment, each dispersion channel 10 has the same winding structure, which improves the consistency of the droplets in each dispersion channel 10.

[0042] As a preferred embodiment, the first inlet 1, the second inlet 2, and each droplet outlet 3 all have a circular cross-section, and the first inlet 1 and the second inlet 2 are both located at the midpoint positions of the first distribution channel 4 and the first distribution flow channel 7, which is beneficial to the symmetry design of the first distribution channel 4 and the first distribution flow channel 7 to facilitate the uniform distribution of the fluid.

[0043] More specifically, in this embodiment, a droplet microreactor as shown in Figure 1 is designed. This microreactor integrates multiple layers of droplet generators up and down. Each layer contains 8 individual droplet generation units, significantly improving the throughput of droplet / microsphere generation.

[0044] The two-dimensional plan view of the droplet microreactor after integrating multiple layers is as shown in Figure 1Shown: The first inlet 1 is the inlet for the continuous-phase fluid, the second inlet 2 is the inlet for the dispersed-phase fluid, and the 8 droplet outlets 3 are all used for collecting droplet products. The 8 third distribution channels 6 are used for distributing the continuous-phase fluid, and the 8 third distribution channels 9 are used for distributing the dispersed-phase fluid. After the continuous-phase fluid in each third distribution channel 6 meets the dispersed-phase fluid in each third distribution channel 9 at their respective connection points, droplets are generated by means of collision and shear, and the generated droplets flow out into the product collector after passing through the enlarged sections of the 8 dispersion channels 6.

[0045] The three-dimensional stereogram of the integrated and enlarged droplet microreactor of the multi-layer droplet generator integrated up and down in this embodiment is as Figure 2 shown, referring to Figure 3 , this embodiment also provides a physical diagram of a single-layer droplet microreactor. In this embodiment, a first fluid inlet pipe connected to all the first inlets 1, a second fluid inlet pipe connected to the second inlet 2, and a liquid collection pipe corresponding to each droplet outlet 3 are further connected to the integrated and enlarged droplet microreactor to facilitate the injection of two-phase fluids and the collection of droplets. In the physical diagram of this embodiment, the width of all channels is 200 microns, the steps at the dispersion structure move upward by 100 microns, the depth of the channels is about 80 microns, the width of the visualization enlarged section is 400 microns, and the inlets and outlets are both connected to flat needles with a diameter of 1 mm.

[0046] Please refer to Figure 4 , Figure 4 is a device diagram for the preparation of water-in-oil emulsions, chitosan microspheres, and silica microspheres. As Figure 4 shown, among them, (a) is a high-pressure injection pump for feeding two-phase fluids, (b) is a microscope connected with a high-speed camera, (c) is a physical enlarged diagram of the integrated microreactor, (d) is an imaging system, and the inserted picture is a partial enlarged diagram during the generation process of chitosan microdroplets, (e) is a physical diagram of the integrated and enlarged droplet microreactor, (f) is a 3D diagram of the integrated and enlarged microreactor, and (g) is a product collector.

[0047] After setting up the device as Figure 4 shown, this embodiment also carried out the following multiple experimental examples to confirm the droplet generation effect of the single-layer droplet microreactor of the present invention.

[0048] Experimental Example 1 The single-layer droplet microreactor in this experimental example is as Figure 1 shown. After the first fluid and the second fluid collide, they enter each droplet outlet 3 through the 8 dispersion channels 6 respectively; in the following experimental examples, as Figure 1 shown, the dispersion channels are divided into upper and lower groups, with a total of four dispersion channels 6 in each group. Among them, the channel numbers of the upper channels are sequentially channel 1-channel 4 from left to right, and the channel numbers of the lower channels are sequentially channel 5-channel 8 from left to right.

[0049] Using an aqueous chitosan solution at 0.5 wt% as the dispersed phase and paraffin oil containing 2% Span 80 as the continuous phase, the two fluids are respectively injected into the two inlets of the droplet microreactor through 5 ml glass syringes by a Harvard high-pressure injection pump. At Q c =10 μL·min -1 , Q d =10 μL·min -1 operating conditions, as Figure 5 shown, all 8 channels can simultaneously generate water-in-oil chitosan droplets. The micro-droplet sizes generated in channels 1 and 5 of the 8 dispersion channels are relatively small, possibly because the experimental tabletop is not flat enough. However, the micro-droplet sizes generated in channels 2, 3, 4, 6, 7, and 8 are basically the same and also have good monodispersity. Even when collected in the product collector, the water-in-oil droplets can still maintain good monodispersity and uniform size.

[0050] As Figure 6 is the droplet generation diagram in the enlarged collection section of the 8 dispersion channels in Experimental Example 1 (operating flow rate: Q c =10 μL·min -1 , Q d =10 μL·min -1 ); It can be seen from Figure 6 that after the flow stabilizes, the generated droplets have extremely high uniformity and monodispersity.

[0051] Experimental Example 2 Figure 7 is the microscopic picture of the droplets generated in the enlarged section under the operating conditions of the continuous phase flow rate Q c =20 μL·min -1 , and the dispersed phase flow rate Q d =10 μL·min -1 . As Figure 7 shown, compared with the operating conditions where the two-phase flow rates are both 10 μL·min -1 , the droplet size is significantly reduced, and the generated droplets have good monodispersity and uniformity.

[0052] Experimental Example 3 Figure 8 is the continuous phase flow rate Q c =100 μL·min -1 , and the dispersed phase flow rate Q d= 100 μL·min -1 Under the operating conditions, the microscopic images of the droplets generated in the amplification section show that the generated droplets have good monodispersity and uniformity. The above examples illustrate that the size of the droplets / microspheres in the present invention can be simply and conveniently achieved by regulating the flow rates of the two phases. Moreover, the asymmetric dispersion structure at the dispersion structure can strengthen the flow field during the droplet generation process, enhance the shear force, and increase the droplet generation frequency. In this experimental example, the droplet generation frequency in a single droplet generator can reach thousands per second.

[0053] Experimental Example 4 Using the ethanol solution of tetraethyl orthosilicate and the ethanol solution of ammonia water as the two-phase fluids of the integrated microreactor, with the flow rate of the continuous phase (ethanol solution of tetraethyl orthosilicate) being 1215 μL·min -1 , and the flow rate of the dispersed phase (ethanol solution of ammonia water) being 243 μL·min -1 (the flow rate ratio of the two phases is about 5:1), by rapidly mixing and mass-transfer coupling with the subsequent aging stage in the integrated amplified microreactor, monodisperse silica microspheres with a size in the range of 110 nm - 300 nm are prepared. Compared with the traditional preparation process, the reaction time for preparing silica microspheres is greatly shortened. The size of the silica microspheres can be precisely regulated by controlling the concentrations of ammonia water and ethyl ester and the flow rates of the two phases. Figure 9 are the scanning electron microscope images of the silica microspheres at different magnification factors. It can be seen that the microspheres have extremely high consistency and monodispersity, and the average size of the microspheres is 380 nm.

[0054] Experimental Example 5 With the flow rate of the continuous phase (ethanol solution of tetraethyl orthosilicate) being 1100 μL·min -1 , and the flow rate of the dispersed phase (ethanol solution of ammonia water) being 220 μL·min -1 (the flow rate ratio of the two phases is about 5:1), by rapidly mixing and mass-transfer coupling with the subsequent aging stage in the integrated amplified microreactor, monodisperse silica microspheres with a size in the range of 110 nm - 300 nm are prepared. Compared with the traditional preparation process, the reaction time for preparing silica microspheres is greatly shortened. Specifically, compared with the traditional stirring process, the reaction time is shortened from hours to dozens of minutes. The size of the silica microspheres can be precisely regulated by controlling the concentrations of ammonia water and ethyl ester and the flow rates of the two phases. Figure 10 are the scanning electron microscope images of the silica microspheres at different magnification factors. It can be seen that the microspheres have extremely high consistency and monodispersity, and the average size of the microspheres is 260 nm.

[0055] In this embodiment, a high-precision lithography technique is adopted. By ensuring that the paths of the two-phase fluid flowing to the droplet generation structure are consistent and machining the rounded corners at the flow turning points, the pressure drop during the flow process is reduced, achieving uniform distribution of the fluid, and further realizing high-throughput preparation of droplets. On the basis of high-throughput preparation, by adding a certain amount of monomers, chemical cross-linking agents, and ultraviolet light curing agents to the two-phase fluid, controllable high-throughput preparation of different types of functional microspheres can be achieved.

[0056] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A droplet microreactor, characterized in that, Integrated by multiple droplet generators, each droplet generator includes a substrate and a fluid distribution channel etched on the substrate. The fluid distribution channels of each layer include a first channel unit for the first fluid distribution and a second channel unit for the second fluid distribution; The first channel unit includes a first inlet, and the first inlet is respectively connected to at least two second distribution channels through a first distribution channel. A plurality of third distribution channels are evenly distributed along the flow direction on each second distribution channel. The first fluid entering through the first inlet enters each third distribution channel along the first distribution channel and each second distribution channel; And the total distance that the first fluid flows through from the first inlet to the outlet end of each third distribution channel is equal; The second channel unit includes a second inlet, and the second inlet is respectively connected to at least two second distribution channels through a first distribution flow channel. The second distribution channels correspond to the second distribution channels one by one; A plurality of third distribution channels are evenly distributed along the flow direction on each second distribution channel, and the third distribution channels correspond to the third distribution channels one by one; The second fluid entering through the second inlet enters each third distribution channel along the first distribution flow channel and each second distribution channel; And the total distance that the second fluid flows through from the second inlet to the outlet end of each third distribution channel is equal; The outlet ends of each third distribution channel and the outlet ends of each third distribution channel are connected in one-to-one correspondence, so that the first fluid and the second fluid collide and shear at the connection to form droplets; The droplets are respectively connected to each droplet outlet through the dispersion channels arranged in one-to-one correspondence; The first inlets, second inlets and each droplet outlet on each layer of droplet generator are connected up and down.

2. The droplet microreactor according to claim 1, wherein Each third distribution channel, each third distribution channel and each dispersion channel are combined into multiple groups. Each group includes a third distribution channel, a third distribution channel and a dispersion channel. The third distribution channel and the third distribution channel of each group are respectively vertically arranged on both sides of the dispersion channel. The outlet ends of the third distribution channel and the outlet ends of the third distribution channel are both connected to the dispersion channel, and the outlet ends of the third distribution channel and the outlet ends of the third distribution channel are arranged out of alignment along the flow direction of the fluid, so that the outlet ends of the third distribution channel and the outlet ends of the third distribution channel are partially opposite.

3. The droplet microreactor according to claim 1, wherein The channel of each third distribution channel near the outlet end is an arc bend, so that the first fluid entering through the third distribution channel and the second fluid entering through the third distribution channel are dispersed under the action of an asymmetric shear force.

4. The droplet microreactor according to claim 1, wherein Each of the second distribution channels and each of the second distribution channels is a meandering structure, and the bends of the meandering structure are all rounded corners.

5. The droplet microreactor according to claim 1, characterized in that, The meandering structures of each of the third distribution channels have the same number of bends; and / or the meandering structures of each of the third distribution channels have the same number of bends.

6. The droplet microreactor according to claim 5, characterized in that, The meandering structures of the third distribution channel and the third distribution channel connected to the same dispersion channel are the same.

7. The droplet microreactor according to claim 1, characterized in that, The inner wall of the fluid distribution channel has a hydrophilic coating or a hydrophobic coating.

8. The droplet microreactor according to claim 1, characterized in that, Each dispersion channel includes a first section and a second section that are connected to each other. The inner diameter of the second section is larger than that of the first section, and one end of the first section is connected to the connection between the third distribution channel and the third distribution channel, and the other end of the second section is connected to the droplet outlet.

9. The droplet microreactor according to claim 1, wherein Each dispersion channel has the same serpentine structure.

10. The droplet microreactor according to claim 1, characterized in that, The first inlet, the second inlet, and each droplet outlet have a circular cross-section. The first inlet and the second inlet are both located at the midpoint positions of the first distribution channel and the first distribution flow path.

Images